Higher than expected OG question

This weekend I did a BIAB partial mash on my stovetop with this recipe:
3# light DME
4# Marris Otter
1.33# Munich
1#Crystal 40
0.5#Aromatic
0.25# Special B
and this mash schedule
7#grains in 9L at 104-110F (20mins), 135-144F (15mins), 152-158F (50mins).

I raised temps by heating the kettle. I rinsed/steeped the grains in 8L of 160F water over the course of 3 batches (I didn't have another big pot). I boiled for 2 hours, chilled to 70F, poured into my pail, and topped to 5g. I realized I forgot to take get an OG reading so I stirred it all up pretty good, and took a sample from the spigot. I expected an OG around 1.062 at 5g, but wound up with 1.072. After checking that sample several times, I pulled another sample and got the same results, so i went along and pitched my yeast. I thought maybe it wasn't mixed enough, so after shaking the s*** out of my pail, I pulled another sample and again got the same result. After that, I checked my hydrometer in water and got a correct reading, so it wasn't that. My temperature readings were based off my thermometer and liquid crystal gauge on the pail.

So my question is, did I really get 90% efficiency or am I missing something here?

are you 100% sure you added the correct amounts of extracts? some LHBS round off in funny ways or may be totally eye balling it. are you sure you have 5 gallons of wort? are you sure the recipe was for a 5 gallon batch size and not 5.5 or 6?

its not imposable you got 90% efficiency but i would be very surprised if you did.

the extract was a 3# Briess bag. the wort was at the 5g mark on the pail. I did the recipe myself and double checked with beersmith.

edit: the grain was probably a little higher, but with spillage and such, I'd say definitely no more than 0.5# total

I'd guess it's a mixing issue. I got crazy readings like that until I started doing a full boil. I even got a wine degasser and stirred the crap out of some worts and still got bogus readings.

Take readings before you top off and then compensate for dilution.

yogensha said:

I'd guess it's a mixing issue. I got crazy readings like that until I started doing a full boil. I even got a wine degasser and stirred the crap out of some worts and still got bogus readings.

Take readings before you top off and then compensate for dilution.

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That's what I usually do, but it slipped my mind. Maybe I'll actually get a bigger kettle so I can do full boils and not have to worry about this again.